10 Aug 2015

Groom MJ et al. BMC Psychiatry 2015; 15: 175.

Adults with ADHD exhibit greater expression of anger and frustration when driving, compared with adults without ADHD, a study from the UK suggests.

This study examined the performance of adults with ADHD (n=22, 16 males) and without ADHD (n=21, 18 males) in a driving simulator along an urban route and a motorway route, hypothesised to exacerbate weak impulse control and deficits in sustained attention, respectively.* Driving performance was assessed via self† and observer reports, and spontaneous comments and eye movements made during driving were recorded.

In terms of driving history, adults with ADHD reported significantly more accidents since passing their test compared with adults without ADHD (p<0.05). During the driving simulation, adults with ADHD showed impaired driving performance compared with adults without ADHD. This was manifested as higher average speed (p<0.05) and more frequent breaking of the speed limit (p<0.05), poorer vehicle control (i.e. taking hands off the steering wheel; p<0.05), slower reactions to sudden events and expression of frustration/anger toward other road users (p<0.05), indicating ADHD-related difficulties in regulating and controlling impulsive behaviour. The type of driving route did not influence ADHD performance, suggesting that adults with ADHD can adjust and maintain speed appropriate to the driving environment and are able to maintain focus on the road ahead.

Researchers concluded that deficits in sustained attention were of less importance in the context of driving performance than problems with control of emotions and motor actions, acknowledging that the 30-minute duration of the assessment may not have been sufficient to adequately assess attentional deficits. The novelty of the driving simulator may also have affected attentional outcomes. Further studies in larger groups with a greater proportion of female participants are warranted.

*The simulated driving route consisted of a built-up urban area, a single carriageway and a three-lane motorway. All parts of the drive contained a variable speed limit, and along the route, five events were programmed to occur unexpectedly (e.g. pedestrians stepping onto the road, sudden slowing of traffic)†Manchester Driving Behaviour Questionnaire